demo: drive Studio against MSW via endpoint swap (no /demo route)

apps/web/package.json

@@ -123,6 +123,7 @@
     "babel-plugin-react-compiler": "^1.0.0",
     "happy-dom": "^20.1.0",
     "jsdom": "^26.0.0",
+    "msw": "^2.7.0",
     "postcss": "^8.5.6",
     "typescript": "^5",
     "vite": "^8.0.7",

apps/web/public/mockServiceWorker.js

@@ -0,0 +1,283 @@
+/* eslint-disable */
+/* tslint:disable */
+
+/**
+ * Mock Service Worker.
+ * @see https://github.com/mswjs/msw
+ * - Please do NOT modify this file.
+ * - Please do NOT serve this file on production.
+ */
+
+const PACKAGE_VERSION = '2.7.0'
+const INTEGRITY_CHECKSUM = 'f5825c521429caf22a4dd13b66e0a1c6'
+const IS_MOCKED_RESPONSE = Symbol('isMockedResponse')
+const activeClientIds = new Set()
+
+self.addEventListener('install', function () {
+  self.skipWaiting()
+})
+
+self.addEventListener('activate', function (event) {
+  event.waitUntil(self.clients.claim())
+})
+
+self.addEventListener('message', async function (event) {
+  const clientId = event.source.id
+
+  if (!clientId || !self.clients) {
+    return
+  }
+
+  const client = await self.clients.get(clientId)
+
+  if (!client) {
+    return
+  }
+
+  const allClients = await self.clients.matchAll({
+    type: 'window',
+  })
+
+  switch (event.data) {
+    case 'KEEPALIVE_REQUEST': {
+      sendToClient(client, {
+        type: 'KEEPALIVE_RESPONSE',
+      })
+      break
+    }
+
+    case 'INTEGRITY_CHECK_REQUEST': {
+      sendToClient(client, {
+        type: 'INTEGRITY_CHECK_RESPONSE',
+        payload: {
+          packageVersion: PACKAGE_VERSION,
+          checksum: INTEGRITY_CHECKSUM,
+        },
+      })
+      break
+    }
+
+    case 'MOCK_ACTIVATE': {
+      activeClientIds.add(clientId)
+
+      sendToClient(client, {
+        type: 'MOCKING_ENABLED',
+        payload: {
+          client: {
+            id: client.id,
+            frameType: client.frameType,
+          },
+        },
+      })
+      break
+    }
+
+    case 'MOCK_DEACTIVATE': {
+      activeClientIds.delete(clientId)
+      break
+    }
+
+    case 'CLIENT_CLOSED': {
+      activeClientIds.delete(clientId)
+
+      const remainingClients = allClients.filter((client) => {
+        return client.id !== clientId
+      })
+
+      // Unregister itself when there are no more clients
+      if (remainingClients.length === 0) {
+        self.registration.unregister()
+      }
+
+      break
+    }
+  }
+})
+
+self.addEventListener('fetch', function (event) {
+  const { request } = event
+
+  // Bypass navigation requests.
+  if (request.mode === 'navigate') {
+    return
+  }
+
+  // Opening the DevTools triggers the "only-if-cached" request
+  // that cannot be handled by the worker. Bypass such requests.
+  if (request.cache === 'only-if-cached' && request.mode !== 'same-origin') {
+    return
+  }
+
+  // Bypass all requests when there are no active clients.
+  // Prevents the self-unregistered worked from handling requests
+  // after it's been deleted (still remains active until the next reload).
+  if (activeClientIds.size === 0) {
+    return
+  }
+
+  // Generate unique request ID.
+  const requestId = crypto.randomUUID()
+  event.respondWith(handleRequest(event, requestId))
+})
+
+async function handleRequest(event, requestId) {
+  const client = await resolveMainClient(event)
+  const response = await getResponse(event, client, requestId)
+
+  // Send back the response clone for the "response:*" life-cycle events.
+  // Ensure MSW is active and ready to handle the message, otherwise
+  // this message will pend indefinitely.
+  if (client && activeClientIds.has(client.id)) {
+    ;(async function () {
+      const responseClone = response.clone()
+
+      sendToClient(
+        client,
+        {
+          type: 'RESPONSE',
+          payload: {
+            requestId,
+            isMockedResponse: IS_MOCKED_RESPONSE in response,
+            type: responseClone.type,
+            status: responseClone.status,
+            statusText: responseClone.statusText,
+            body: responseClone.body,
+            headers: Object.fromEntries(responseClone.headers.entries()),
+          },
+        },
+        [responseClone.body],
+      )
+    })()
+  }
+
+  return response
+}
+
+async function resolveMainClient(event) {
+  const client = await self.clients.get(event.clientId)
+
+  if (activeClientIds.has(event.clientId)) {
+    return client
+  }
+
+  if (client?.frameType === 'top-level') {
+    return client
+  }
+
+  const allClients = await self.clients.matchAll({
+    type: 'window',
+  })
+
+  return allClients
+    .filter((client) => {
+      return client.visibilityState === 'visible'
+    })
+    .find((client) => {
+      return activeClientIds.has(client.id)
+    })
+}
+
+async function getResponse(event, client, requestId) {
+  const { request } = event
+
+  const requestClone = request.clone()
+
+  function passthrough() {
+    const headers = new Headers(requestClone.headers)
+
+    const acceptHeader = headers.get('accept')
+    if (acceptHeader) {
+      const values = acceptHeader.split(',').map((value) => value.trim())
+      const filteredValues = values.filter(
+        (value) => value !== 'msw/passthrough',
+      )
+
+      if (filteredValues.length > 0) {
+        headers.set('accept', filteredValues.join(', '))
+      } else {
+        headers.delete('accept')
+      }
+    }
+
+    return fetch(requestClone, { headers })
+  }
+
+  if (!client) {
+    return passthrough()
+  }
+
+  if (!activeClientIds.has(client.id)) {
+    return passthrough()
+  }
+
+  const requestBuffer = await request.arrayBuffer()
+  const clientMessage = await sendToClient(
+    client,
+    {
+      type: 'REQUEST',
+      payload: {
+        id: requestId,
+        url: request.url,
+        mode: request.mode,
+        method: request.method,
+        headers: Object.fromEntries(request.headers.entries()),
+        cache: request.cache,
+        credentials: request.credentials,
+        destination: request.destination,
+        integrity: request.integrity,
+        redirect: request.redirect,
+        referrer: request.referrer,
+        referrerPolicy: request.referrerPolicy,
+        body: requestBuffer,
+        keepalive: request.keepalive,
+      },
+    },
+    [requestBuffer],
+  )
+
+  switch (clientMessage.type) {
+    case 'MOCK_RESPONSE': {
+      return respondWithMock(clientMessage.data)
+    }
+
+    case 'PASSTHROUGH': {
+      return passthrough()
+    }
+  }
+
+  return passthrough()
+}
+
+function sendToClient(client, message, transferrables = []) {
+  return new Promise((resolve, reject) => {
+    const channel = new MessageChannel()
+
+    channel.port1.onmessage = (event) => {
+      if (event.data && event.data.error) {
+        return reject(event.data.error)
+      }
+
+      resolve(event.data)
+    }
+
+    client.postMessage(
+      message,
+      [channel.port2].concat(transferrables.filter(Boolean)),
+    )
+  })
+}
+
+async function respondWithMock(response) {
+  if (response.status === 0) {
+    return Response.error()
+  }
+
+  const mockedResponse = new Response(response.body, response)
+
+  Reflect.defineProperty(mockedResponse, IS_MOCKED_RESPONSE, {
+    value: true,
+    enumerable: true,
+  })
+
+  return mockedResponse
+}

apps/web/src/components/agent-connect.tsx

@@ -22,14 +22,17 @@ import { Label } from "@ui/label";
 import { Popover, PopoverContent, PopoverTrigger } from "@ui/popover";
 import {
 	AlertCircle,
+	ArrowRight,
 	CheckCircle2,
 	Loader2,
+	Play,
 	Settings,
 	Terminal,
 	Unplug,
 	Wifi,
 } from "lucide-react";
 import { useEffect, useState } from "react";
+import { useAgentEndpoint } from "@/lib/agent-endpoint";
 import { useAgentContext } from "@/lib/agent-provider";
 
 const AGENT_CONFIG_KEY = "stackpanel-agent-config";
@@ -78,6 +81,7 @@ export function AgentConnect({ onConnected }: AgentConnectProps) {
 		clearPairing,
 		connect,
 	} = useAgentContext();
+	const { useDemo: enterDemo, bootingDemo } = useAgentEndpoint();
 
 	const [pairingToken, setPairingToken] = useState("");
 	const [isPairing, setIsPairing] = useState(false);
@@ -258,17 +262,39 @@ export function AgentConnect({ onConnected }: AgentConnectProps) {
 						</div>
 					</div>
 
-					<Button
-						onClick={() => {
-							clearPairing();
-							connect();
-						}}
-						size="sm"
-						variant="outline"
-					>
-						<Wifi className="mr-2 h-4 w-4" />
-						Retry Connection
-					</Button>
+					<div className="flex flex-wrap items-center gap-2">
+						<Button
+							onClick={() => {
+								clearPairing();
+								connect();
+							}}
+							size="sm"
+							variant="outline"
+						>
+							<Wifi className="mr-2 h-4 w-4" />
+							Retry Connection
+						</Button>
+						<Button
+							className="bg-amber-500 text-amber-950 hover:bg-amber-500/90"
+							disabled={bootingDemo}
+							onClick={() => {
+								void enterDemo();
+							}}
+							size="sm"
+						>
+							{bootingDemo ? (
+								<Loader2 className="mr-2 h-4 w-4 animate-spin" />
+							) : (
+								<Play className="mr-2 h-4 w-4" />
+							)}
+							Try the Demo
+							<ArrowRight className="ml-2 h-3 w-3" />
+						</Button>
+					</div>
+					<p className="text-muted-foreground text-xs">
+						No install required. The demo runs entirely in your browser
+						against fixture data.
+					</p>
 				</CardContent>
 			</Card>
 		);